Flotation apparatus



March 31, 1931. w BUTCHART 1,798,451

FLOTATION APPARA'I 'US Filed April 25, 1927 Patented Mar. 31, 1931 PATENT OFFICE WILLIAM A. BUTCHART, F JOPLIN, MISSOURI FLOTATION APPARATUS Application filedApril 23,

My invention relates to apparatus for the,

extraction of values from ores by flotation, in which air and mechanical agitation are employed to produce a mineral bearing froth which rises to a point of overflow in the tank or vessel in which the process is performed. It is an object of the present invention to provide in a flotation apparatus of the above stated type, novel and useful improvements 1 in the construction and arrangement of the aerating and agitating means, which add to their efficiency and expedite and further the separative and froth-producing actions so as to effect a substantially clean separation of the values from the gangue or barren rock of the material under treatment.

Another object is to provide for the distribution of the air in the material through the medium of one or more porous surfaces which by their position at an angle greater than the angle of repose of the solids suspended in the material, prevent blanketing or blinding of the air passages by the precipitation of settling solids to the bottom of the tank in which the process is carried on.

Further objects of the invention reside in details of construction particularly with reference to the agitating element of the apparatus, all of which will be fully brought out in the course of the-following description.

In the accompanying drawings in which like parts are similarly designated.

Figure 1 represents a partially sectional elevation of a flotation machine in which the present improvements are embodied,

Figure 2, an end elevation of the machine, looking in the direction of the arrow A in Figure 1, and

Figure 3, a section taken on the line 3-3 Figure 1.

A tank or vessel designated in its entirety by the reference numeral 5, has sides 6 sloping toward a fiat bottom 7. In the upper portions of the sides are openings for the overflow of the mineral-bearing froth across outwardly slanting aprons 8 and in one of the end walls of the tank adjacent the bottom of the same, is an outlet 9 for tailings connecting with an upright box 10.

A vertical partition or weir 12 in the box 1927. Serial No. 186,058.

determines the liquid level in the tank, and a sliding gate 13 overlapping the upper edge of the weir, provides a convenient means for varying the height of the liquid level in the vessel.

The aerating element of the apparatus is disposed in the lower portion of the tank intermediate of the sloping sides thereof. It consists in its preferred form, of a frame composed of an upright board 14 extending lengthwise of the tank, ribs 15 at opposite sides of the board extending lengthwise in a central position with'relation to the upper and lower edges thereof, and a covering 16 of canvas or other porous material which is stretched around the frame.

The covering being spaced from the sides of the board by the ribs, forms foraminous air-chambers which are connected by suitable openings 17 in the board. The canvas covering has at an end of the frame, a sleeve 18 to connect the air chambers with a pipe 19 leading to a conveniently located source of air under pressure.

The aerating element is made stationary by fastening the ends of its frame to the end walls of the tank as shown in Figure 1 of the drawings. The aerating element per se is the subject of an application for patent Serial N 0. 175,562 filed by me onthe 15th day of March, 1927. i

' The mechanical agitating element placed in cooperative relation to the aerating element, comprises a shaft 20 supported for oscillation in boxes 21 on the end walls of the tank. The shaft carries a pair of brackets 22 rigidly secured by set-screws 23, to which are attached arms 24 preferably composed of diverging members, which extend downwardly into the tank in spaced relation to the end walls of the same.

Fastened at the lower ends of the arms are rakes or paddles 25 of angle section which extend parallel to the bottom of the tank slight- 1y below and at opposite sides of the aerating element. The structure is reenforced by braces 26 extending between the diverging members of the arms at the lower ends thereof.

' Rigidly mounted upon an end of the shaft,

exteriorly of the tank, is a rocker arm 27 which is forked or bifurcated to admit the wrist pin 28 of a crank 29 at the end of a drive shaft 30. The last-mentioned shaft is supported for rotation in a bearing on a bracket 31 fastened to the adjacent end wall of the tank.

The shaft is held against longitudinal displacement by a collar 32 and a pulley 83 on the shaft provides for its connection with a motor or other source ofmechanical energy.

In the operation of the apparatus the pulverized ore and water, formed into a pulp, are fed into the tank together with a suitable frothing agent, through an inlet conduit 34.

The material fills'the tank to a level determined by the weir in the tailings box, and power is applied to the pulley. The cranx on the rotating drive shaft cooperates with the bifurcated arm 27 to impart an oscillating movement to the shaft 20, thereby causing the paddles 25 to reciprocate below the aerating element.

A suitable quantity of air under pressure is admitted to the air chambers between the board and the foraminous sides of the aerating element, and this air is forced through the sides into the pulp and produces a froth which carries the mineral in the pulp to the liquid level whence it passes across the overflow aprons.

The oscillating agitating element, at the same time maintains the solids in the pulp in suspension and prevents them from settling to the bottom of the tank.

The supply of air to the aerating element may be regulated by one or more valves in the supply pipe, not shown in the drawings.

It will be evident that the porous sides of the air chambers extending at a precipitous angle greater than the angle of repose of the solids in suspension, are kept free from settling matter thus permitting of the constant unobstructed distribution of air in the material to the full capacity of the element throughout the operation.

The mechanical agitating element prevents accumulation of settling matter upon the bottom of the tank so that the flow of liquid through the tank may move such solids to the outlet opening. The aeration and mechani cal agitation cooperate to produce a continuous overflow of froth in any desired quantity. and effect a substantially clean separation of the minerals from the gangue by upward movement of the froth in which the minerals are held.

Having thus described my invention, what I claim and desire to secure by Letters Patent 1. In flotation apparatus, a tank, an aerating element for the discharge of air into material in the tank, an oscillatory agitation element having paddles below the aerating element and mechanism to effect an oscillating movement of the agitation element.

2. In flotation apparatus, a tank, an air chamber having precipitous porous sides for the discharge of air into material in the tank, a reciprocating agitating element below the air chamber and mechanism to effect a reciprocating movement of the agitating element.

3. In flotation apparatus, a tank, an air chamber having precipitous porous sides for the discharge of airinto material in the tank, an oscillatory agitating element having paddles at opposite sides of the air chamber, and mechanism to effect an oscillating movement of the agitating element.

4. In flotation apparatus, a tank, an aerating element for the discharge of air into material in the tank, and an oscillating agitating element comprising a shaft above the aerating element, depending arms on the shaft on either side of the aerating element, and agitating paddles on the arms below the aerating element.

5. In flotation apparatus, a tank, an aerating element for the discharge of air into material in the tank, and an oscillating agitating element comprising paddles at either side of the aerating element, the aerating element being in the arc of oscillation of the agitating element.

6. In flotation apparatus, an elongated tank, an aerating element extending substantially the length of the tank for the discharge of air into material in the tank and an oscil lating agitating element extending substantially the length of and below the aerating element.

In testimony whereof Ihave aflixed my signature.

WILLIAM A. BUTCHART. 

